present invention is directed to a method for exchanging cutting tools in a platen press and to a device for accomplishing this method, especially for the exchange of the upper and the lower tools of the cutting section of the platen press.
The cutting section of a platen press usually comprises a pair of arms which extend perpendicularly to the side of the frame of the press on the operator's side. In a way of execution, these arms may pivot around an axle located close to the external face of the side frame so as to be bent back toward the frame when they are not in use. This solution increases the space available in front of the machine and allows the operator to move easily close to the machine.
In another way of execution, for instance with machines processing sheets of smaller sizes, these arms may be firmly fixed and, thus, extend permanently perpendicularly to the frame's side face.
On the inner face, each arm includes two grooves in which the cutting tools are slid when extracted from the cutting section. Moreover, each arm includes a pivoting device which is located at the end opposite the connection of the arms with the frame. This pivoting device is destined to allow the cutting tool to be pivoted up to 180.degree. around a horizontal axis.
A new job, which has to be achieved with the platen press, requires the exchange of the previously-used tools with subsequently-used tools proper to this new job.
In the devices known up to now, the exchange or removal of the cutting tools is usually executed with the help of an auxiliary carriage which comprises two lengthwise beams oppositely arranged between two lateral frames. On the inner faces of these beams, these lengthwise beams will have two grooves of which a pair is to carry a subsequently-used tool. For job changes, the carriage is brought in front of the space existing between the arms of the cutting section and, once one of the tools previously used in the platen press has been slid onto the arms, then the tool is inserted in the pair of grooves left free on the carriage and is locked in a horizontal position in these grooves and the assembly, which consists of the subsequently-used tool, and the previously-used tool and the lengthwise beams is then pivoted up to 180.degree. around a horizontal axis so as to have the subsequently-used tool positioned exactly in front of the grooves of the arms. Then, the new tool is unlocked and inserted in the cutting section where it will be locked again in the press. The carriage can then be moved away from the front of the machine and the previously-used tool be unloaded in order to have the second subsequently-used tool loaded and the operation started again.
Among other drawbacks, this way of changing tools has the disadvantage of implying twice the loading and once the unloading of the tools on the carriage, which operations are time-consuming and have a negative influence on the production of the platen press which is to be at a standstill during the whole process. Moreover, should the tools be poorly locked on the carriage, it could happen that one of them, which may reach a weight of 50 kilograms, may fall off during the rotation around the horizontal axis with the risk of hurting the operator. It should also be mentioned that this solution is cumbersome and requires an important space in front of the platen press, which fact is not compatible with an optimal use of the space available close to the machine.